I'm not great with the old stuff and it was originally with schildback.wallet. All the GitHub data is there, but need some assisatnce to decrypt it and check it.
Do a run down on this thread first:
[HOW-TO] Export Bitcoin private keys (in WIF) from Bitcoin Android (schildbach)See if anything in the OP and replies look similar to your "
Master Key".
Also, that's posted in the dedicated board for Bitcoin Wallet for Android (
schildbach) so try to search the board and you may find a thread or two with similar issue that was solved.
If nothing helps, you should describe what you have in more detail like no-actual-examples and the feasility of decoding it (
if you know or at least have an idea of the password).